1. Field of the Invention
The present invention concerns a folding apparatus for automatic folding of flatwork, in particular articles of clothing, with a machine frame, with a longitudinal folder and a subsequently disposed transverse folder, two laundry conveyors being provided disposed in the transverse folder one behind the other in the conveying direction of a flatwork article arriving from the longitudinal folder, and being spaced apart by a gap stretching essentially across the entire width of the transverse folder, and a flatwork article being introducible into the gap while a first transverse fold is made.
2. Discussion of the Background
Folding apparatuses of this type are known. They generally comprise a feed conveyor, on which a flatwork article to be folded is placed, spread out, and is fed to the folding device. The flatwork article arrives at a longitudinal folder, where it is folded once or twice, depending upon the width. The flatwork article lies thereby on belts of a conveyor, one or both of the side edges of the flatwork article parallel to the conveyor belts being turned inward using a folding blade while forming a longitudinal fold. The longitudinally folded flatwork article is conveyed further and is passed to a transverse folder adjoining the longitudinal folder. Here there are usually two laundry conveyors, spaced apart, one behind the other in the conveying direction of the flatwork article. Between the conveyors there is a gap. The flatwork article is conveyed over the two said conveyors until the place on the flatwork article where a transverse fold is to be made lies over the said gap. The conveyor operated subsequently in the said conveying direction reverses its conveying direction while at the same time the flatwork article is pressed into the gap while a first transverse fold is made using a folding blade or an air blast. The gap stretches from the conveyor surface of the said laundry conveyor inclined downward, preferably at an angle of about 90.degree.. The flatwork article, now folded once crosswise, passes through this gap and is turned to the left or to the right at the exit point while a second transverse fold is formed, and is thereby placed on a further laundry conveyor disposed below the two said laundry conveyors and which extends to the left and to the right of the gap. The turning of the flatwork article to the one side or to the other is determined by the folding program, depending upon whether the leading edge of the folding flatwork article is supposed to lie inside or outside. The further laundry conveyor is also designed to carry the flatwork article out of the folding apparatus after the second transverse fold has been made.
Although a folding apparatus of this kind, as can be seen in principle in FIG. 1, operates rather reliably, certain difficulties nevertheless arise which must be paid attention to in folding flatwork articles of differing thicknesses, such as, for example, a thin blouse or thick work clothes. The gap opening or gap width is to be adjusted each time to the thickness of the flatwork article so that the article can be perfectly conveyed along the gap. The range of adjustment is large. Up to now the gap width has been adjusted to the flatwork article using spring means. In introducing a flatwork article into the gap using the folding blade, the gap width opens as far as necessary owing to the force of the flatwork article itself. Difficulties have arisen when the gap opening has been adjusted to the thinnest flatwork to be folded and the opening force for thick flatwork has been too great, or when, to prevent the foregoing, the basic setting of the gap width is adjusted to flatwork of average thickness, and extremely thin flatwork articles therefore could no longer be conveyed into the gap perfectly, but practically fell down into the gap. Foreseen also has been manual adjustment to the most advantageous gap width prior to folding a series of articles of the same kind. This is laborious and requires an experienced person to avoid several attempts being made.
Until today a similar problem has arisen in carrying out the completely folded flatwork article on the aforementioned further laundry conveyor. Especially with thick flatwork, the outer-lying leading edge of the flatwork article has been caught at the too narrow inlet of this conveyor. The article has had to be removed and refolded.
Due to these problems, allowances have had to be made for reduced quality in folding.
It is the object of the present invention to eliminate these described difficulties by improving the folding apparatus.
The first named difficulty is overcome with a folding apparatus wherein means are foreseen to change the gap width and to adjust to the type of flatwork article before the flatwork article is introduced.
The second named difficulty can be avoided if the folding apparatus is additionally equipped so that below the two laundry conveyors there is a further laundry conveyor, wherein the further laundry conveyor is driven reversibly and has two upper conveyor sections and one lower conveyor section, the first upper conveyor section being disposed below the first laundry conveyor and the second upper conveyor section being disposed below the second laundry conveyor, and the lower conveyor section of the further laundry conveyor extending below both of the upper conveyor sections, and adjustment means are provided to change the course of belts of the lower conveyor section of the further laundry conveyor in the area of the gap, or, respectively of the ends turned toward each other of the upper conveyor sections.
Foreseen as means to adjust the gap width are preferably pneumatic cylinders. However, other means could be used just as well, such as, for example, hydraulic cylinders, electromotors with gearing, etc. In addition to this adjustment of the gap width, the previously mentioned spring action could still be maintained for fine adjustment only; this would be when the closing cylinder for the gap width is driven by an adjustable pressure reducing valve.
The type of flatwork article, such as a blouse, a jacket, apron, overall, etc., can be entered, for example, into a data entry device, and conseqently its thickness can be determined to a large extent, and thus the gap width. This type of operation is advantageous when a series of like flatwork articles has to be folded.
Another embodiment foresees direct determination of the thickness of the flatwork article already folded longitudinally using, for example, a measuring device which can be disposed in the longitudinal folder or directly at the entrance to the transverse folder. This can take place, for example, in that using a photoelectric barrier with a light band, the layer height of the longitudinally folded flatwork article on conveyor belts is measured.
A third possibility foresees measuring the length of the flatwork article to be folded with a measuring device, and of categorizing the flatwork article based on the length. For example, blouses, aprons, overalls have typical lengths for their categories, with relatively small deviations. Based on the type of flatwork article determined in this way, the gap width can be adjusted. To measure the length of a flatwork article a light barrier would suffice which can measure the time it takes the flatwork article to pass through it. Using the known conveying speed, the length of the flatwork article can be easily calculated.
A preferred embodiment of the transverse folder foresees only one laundry conveyor being displaceably disposed to change the gap width. In the embodiment shown, this is the conveyor disposed after the gap, seen in the conveying direction of the flatwork article. The conveyor disposed before the gap is thus stationary. Interchanging the stationary and displaceable laundry conveyors would also be conceivable. Adjustment of the gap width can be controlled in such a way that this can take place before introduction of the flatwork article into the gap. It could also operate in that just when the flatwork article is introduced into the gap, the gap is completely open, or is opened completely for a short time, and only a little while later, after the formation of the transverse fold, the gap width is set to the value determined previously.
A preferred embodiment foresees that the gap width can assume three predefined values using adjustment means. In feeding the flatwork article arriving in the transverse folder into the gap, the folding blade and/or air blast can always be introduced at the center of the gap, owing to its being disposed on the pivoted lever, regardless of the position of the displaceable laundry conveyor.
While the direction of feed of a flatwork article into the transverse folder is essentially horizontal, and is determined by the support surface of the two laundry conveyors one behind the other, the gap extends downward preferably at approximately a right angle to the said direction. Disposed at the lower end of the gap is a further laundry conveyor, which extends to the right and to the left, relative to the gap and about parallel to the said direction of feed of the flatwork article. Depending upon the type of fold, the flatwork article is turned to the right or to the left to make a second transverse fold. The completely folded flatwork article is carried out of the transverse folder via the further laundry conveyor, which is at the same time the discharge conveyor. By means of the adjustability of the belt of the further conveyor in the area of the lower end of the gap, both the turning of the flatwork article arriving through the gap in the desired direction is facilitated and above all the completely folded flatwork article can be carried out without piling up at any location.
Particularly advantageous is that the belt of the further conveyor can be lowered in the area of the lower gap end before carrying out the flatwork article so that the entrance to the discharge conveyor section is wider and the piling up of thick flatwork articles can be prevented.